sign

The root sign comes from Latin signum — a mark, token, or seal — and its verb signāre, "to mark." In Roman life a signum was anything that stood for something else: the standard a legion carried into battle, the seal pressed into wax to prove a letter was genuine, the mark a shepherd cut into an animal's ear. A signum was a visible thing that carried meaning beyond itself.

That single idea — a mark that means something — fans out into a surprisingly wide family.

The most literal members keep the "mark" sense intact:

- sign — a mark or board that tells you something (a road sign, a sign of trouble).
- signal — a signum sent across distance: a sign you actively convey (a hand signal, a radio signal).
- signature — your personal mark, the signum that proves you were here.
- insignia — the marks (in- + signa, plural) that show rank or membership: badges, emblems, a colonel's stars.

Then comes a clever twist. Latin glued signum to facere ("to make") → significāre, "to make a sign," i.e. to mean. From this we get:

- signify — to make a sign, to mean.
- significant — literally "sign-making": something that carries meaning. Because what carries meaning matters, the word slid into its everyday sense "important, sizeable."
- significance — the meaning or weight a thing carries.

Prefixes generate the rest, and here the meanings jump in instructive ways:

- de- (out, down) + signāre → design: to mark out a plan before building it. A designer first traces the lines.
- designate / designation — to mark someone out for a role.
- re- (back) + signāre → resign: to sign back, to formally give up a post by un-signing it; and emotionally, to give yourself up to fate.
- con- (together) + signāre → consign: to sign goods over to someone's care — to hand off, to entrust.
- as- (to) + signāre → assign: to mark something to a person — to allot a task.
- ensign — a signum on a pole: a banner or flag, and later the junior officer who carried it.

The pattern to hold onto: at the center sits a mark with meaning. Add "make" and you get meaning itself (signify, significant). Add a prefix and you get what you do with the mark — draw it out (design), give it back (resign), hand it over (consign, assign).